1. Field of the Invention 
The invention relates to a mass flow rate measuring device which works according to the Coriolis principle and has a measuring line, whereby a tension sensor is provided and the tension sensor is attached to the measuring line in such a way that the mechanical tension of the measuring line can be recorded with the tension sensor. The invention further relates to a process for measuring the pressure with a mass flow rate measuring device which works according to the Coriolis principle and has a measuring line. 
2. Description of the Prior Art 
A Coriolis mass flow rate measuring device of the kind mentioned in the beginning is known, for example, from the DE 42 24 379 C1. With this Coriolis mass flow rate measuring device it is proposed to provide a length variation sensor recording changes in the vibration length of the measuring line for correcting the measured value of the mass flow rate as a function of the vibration length and the tension. If in addition, a temperature sensor recording the temperature of the measuring line is provided for correcting the measured value, it is possible, to correct the measured value using temperature variations in the measuring line on the one hand, and on the other, length variations in the measuring line, i.e. of the vibration length of the measuring line, which influence the measured value. Thus it is possible to reduce or eliminate measuring errors due to temperature variations in the measuring line, in particular those which result from external forces.  
Due to the fact that with this Coriolis mass flow rate measuring device known in the art, a length variation sensor recording variations in the vibration length of the measuring line is provided, it is possible to take into account a change in the vibration length influencing the vibration frequency of the measuring line and the axial state of tension of the measuring line, which allows measuring errors to be reduced or eliminated. If a temperature sensor is additionally provided it is possible to reduce or eliminate those measuring errors which are, on the one hand, due to temperature variations in the measuring line, and on the other hand, due to forces which act upon the measuring line from outside. The length variation signals given out by the length variation sensor are thus a direct measure for variations in the vibration length of the measuring line, independent of their origin, and an indirect measure for variations in the axial state of tension of the measuring line, also independent of their origin. The length variation sensor for recording the variations in the vibration length of the measuring line therefore makes it possible to record variations in the vibration length of the measuring line and variations in the axial state of tension of the measuring line and to reduce or eliminate resulting measuring errors when determining the measured value. 
The previously described Coriolis mass flow rate measuring device known in the art with a tension sensor for recording the mechanical tension in the measuring line thus offers the possibility to output corrected measured values for the mass flow rate. An output of additional values which have nothing to do with the rate of flow through the measuring line of the Coriolis mass flow rate measuring device is, however, not envisaged. Therefore, if the recording and output of further parameters such as the pressure of the medium flowing through the measuring line of the Coriolis mass flow rate measuring device is of interest, a suitable additional sensor must be provided. 